“Well, I just think we have to approach it game by game,’’ said Rask, who turned away 29 shots the Blackhawks put on net.

He turned away all 12 shots he faced in a frantic third, making one last brilliant stop after he attempted to skate off to allow an extra attacker to come on, only to retreat when he saw his team turn the puck over in the neutral zone.

Rask made the stop then departed the ice, only to watch from there as Dave Bolland scored into the empty net.

“We got to go home and it’s a must-win,’’ Rask said. “Good thing we’re at home. So, we’ll focus on Monday and then we’ve got to play a really solid 60-minute effort in order to have a chance.’’

The Bruins will have to hold serve at home in Game 6 likely without the services of Patrice Bergeron, who skated only two shifts in the second period before leaving the game, and then being transported to a local hospital, with an undisclosed injury.

Jim Davis/Globe Staff

Bruins goalie Tuukka Rask has some unwanted company in the Blackhawks’ Marcus Kruger, but Adam McQuaid does his best to clear the crease.

“You know how big of a player and leader he is with us, but it’s nothing we can do about it,’’ Rask said. “We have to move on and trust the guys who are going to step in that they’re going to do a good job.’’

After he gave up six goals on 47 shots in Game 4, Rask came out Saturday night intent on stopping everything he saw. He had yielded four or more goals on five occasions this postseason, but in each instance managed to bounce back from those porous performances to post a 4-0 record, with a 1.33 goals-against average and a .959 save percentage.

Until, that is, the Blackhawks — and Patrick Kane in particular — put a blemish on that record.

“Well, they have had two good games in a row, and the way the goals were scored, they were scored close around the net,’’ said Bruins coach Claude Julien. “Kane scored three goals in the last two games, and he’s very good at kind of finding those quiet areas and sliding into the right spot. That’s why he’s a good player and scores a lot of goals.

“We just maybe have to have a little bit more awareness around our net because both goals were scored the same way.’’

Kane gave the Blackhawks a 1-0 lead at 17:27 of the first period when he rapped home a goalmouth rebound of Johnny Oduya’s hard slapper from the left point that fractured the shaft of Seidenberg’s stick.

On the second goal, at 5:13 of the second period, Kane swooped in and roofed a backhanded rebound of Bryan Bickell’s wraparound bid.

Just as was the case in Game 4, the Blackhawks victimized Boston’s top defensive pair of Zdeno Chara and Dennis Seidenberg, both of whom were on the ice for both of Kane’s goals.

Asked if the Blackhawks were effective in establishing a net-front nuisance, as they did in Game 4, Rask said, “I don’t think so. I think it was the same. They like to lose guys behind the net and sneak behind our D, but I didn’t see any more traffic than I had in the past.’’

When Chara atoned at 3:40 of the third with a hard slapper from the left circle that beat goaltender Corey Crawford on the glove side, the Bruins were energized. The goal came as the Bruins tried to claw back without Bergeron.

Asked if he liked the way the team responded to the challenge, Rask said, “Yeah, but it’s kind of sad that you got to lose a guy like that to wake the team up and start battling out there. You’re in the Final and you play 20 minutes and it’s not going to be good enough to win you a hockey game. So we have to realize that it’s going to take a full 60 minutes.

“We’re going to have some new bodies and new lines on Monday and everybody needs to play 110 percent and leave their heart out on the ice.’’